I didn't mean to suggest Canadane was wrong, I meant to say the bottom line reason is this is what they wanted to do. They could have done other things, they just didn't. They could have had other designs, they didn't- this is what they wanted.
I don't even say that like "yaaay this is what they wanted, I love it don't touch it!" lol (I don't, not that others are not allowed to like it, this might be exactly what someone else wanted, opinions and all are free to have lol)- it's just clear while they could have done x y z and any reason why they didn't is honestly just superficial, as in the reason they don't do it now is not because it's an unimaginable solution - it's that they didn't want to make that sort of content, you could construct around Canadane's given issue, of course more work but you could do stuff (and if you were designing form the beginning rather than after the fact you wouldn't even have to "design around" it since you could have had it be a key part of the design in the first place; a priori vs a posteriori). Even you yourself make examples of ways they might have done what OP wanted without the issues mentioned by others. Ultimately as I said "this is what it is because this is what they chose to do".
It's different than perhaps they create something and an unintentional consequence happened because of this, this is they made a content that performs exactly how they designed it to perform and so the answer as to why it doesn't do other things while you might be able to point out challenges at the end of the day it's because it's doing what they made it do. Why are Trust members not part of your squadron? Because they decided they didn't want to do that. You might come up with other reasons why that add challenges, but in that situation it was clear it was a design choice not a failure of thought. Blue Mage does what it was designed to be, of course you can like or not like that and ask or not ask for changes- but I mean to say "why is it the way it is now" and my answer is "because this was their vision" you might suggest issues which may be hurdles they'd have to consider (as with the implementation of almost literally anything, always challenges to consider), but in the end "this is what they were making because this is what they wanted to make".
Which you can also back up by the fact that in ARR beta, long long long ago, Yoshida had already detailed out some thoughts on what blue mage would be (a side content / mini game with a fairly large spell book), it's not like they arrived to this job after long periods of hard challenging deliberation and technical impossibilities, it was thought to be this way since before ARR was even published. They could have done something different, they didn't, and it was by choice.
So if it was looking like I was trying to tell them their answer was bad or something then that wasn't my intention.